PROJECT SUMMARY/ABSTRACT The Tisch Cancer Institute (TCI) Mouse Genetics Shared Resource Facility (MGSRF) provides TCI members with access to state-of-the-art facilities for the production of transgenic and knockout cancer models in mice, as well as related rodent embryology techniques. The MGSRF produces transgenic mice by injection of DNA fragments into pronuclear stage single-cell mouse embryos, and assists laboratories with the production of targeted mutant lines of mice through the use of mouse embryonic stem (ES) cells or CRISPR/Cas9 gene editing. In addition to the creation of novel mouse lines, the MGSRF assists TCI laboratories with the maintenance of existing lines through the cryopreservation of sperm, and with the import of novel lines from other institutions by recovering mice from cryopreserved embryos or sperm, live embryos, or through the use of IVF rederivation of individual males that are shipped to ISMMS. This Shared Resource Facility has a long-standing history of creating mice for TCI laboratories, and the MGSRF?s role in the cancer programs will continue to strengthen and enhance the ability of TCI members to conduct cutting-edge cancer research using novel mutant mouse models.